Macro Calculator
Get your daily protein, carbs and fat targets for your goal.
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Macronutrients are the three nutrients that supply energy: protein, carbohydrate and fat. Your macros are how your daily calories are split between them, measured in grams. Calories decide whether you gain or lose weight, but the split decides how much of that change is muscle versus fat, how well you train, and how full you feel. This macro calculator takes your daily calorie target and bodyweight and returns a clear protein, carb and fat breakdown in grams, along with the percentage of calories each one provides, tailored to whether you want to lose fat, maintain or build muscle.
How the macro split is calculated
We anchor protein to your bodyweight rather than to a fixed percentage, because protein needs scale with how much body you have to maintain. The target is 2.2 g per kilogram when cutting, 1.8 g when maintaining, and 2.0 g when building muscle, in line with the ISSN position stand range of 1.6 to 2.2 g per kilogram. Fat is set to 25% of your total calories, enough for hormone health without crowding out carbohydrate. Carbohydrate then fills whatever calories are left, fuelling your training and recovery.
Protein and carbohydrate each provide 4 calories per gram, while fat provides 9. For example, a 75 kg lifter eating 2,500 calories to maintain gets 135 g of protein (1.8 x 75, or 540 calories), 69 g of fat (25% of 2,500 is 625 calories, divided by 9), and the remaining 1,335 calories as carbohydrate, which is 334 g. That works out to roughly 22% protein, 25% fat and 53% carbs.
How to adjust your macros
The split this calculator gives you is a balanced default, not a rule. Protein should stay high and roughly fixed, but the fat and carbohydrate balance is flexible. If you prefer a lower-carb or keto-leaning diet, shift calories from carbohydrate toward fat; if you train hard and want more fuel, do the opposite and keep fat near the 25% floor. As long as protein and total calories hold, your weight and body composition results will be very similar either way.
At very low calorie targets the standard split can leave too little room for carbohydrate, so the calculator trims protein and fat slightly to keep the numbers realistic. This mostly affects aggressive cutting diets and small bodyweights.
Why protein gets priority
Of the three macros, protein is the one worth getting right first. It preserves muscle in a calorie deficit, drives muscle growth in a surplus, and is the most filling per calorie, which makes a diet easier to stick to. Carbohydrate and fat are largely interchangeable as energy sources, so spend less effort balancing them precisely. Hit your protein target most days, stay near your calorie goal, and the remaining split is a matter of personal preference and training demands.
How to use
- 01
Enter your details
Add your stats and activity level so we can estimate your daily calories.
- 02
Choose a goal
Lose fat, maintain or build muscle — this sets your calories and protein.
- 03
See your macros
The result shows grams of protein, carbs and fat plus the percentage split.
Frequently Asked Questions
For most goals 1.6–2.2 g of protein per kilogram of bodyweight is ideal; cutting sits at the higher end to protect muscle.
There is no single best split. We anchor protein to your bodyweight, set fat at about 25% of calories, and fill the rest with carbohydrates.
Total calories drive weight change; macros determine body composition, performance and how full you feel.
Yes. You can shift carbohydrate calories toward fat for a lower-carb approach as long as protein stays high.
How to Calculate Your Macros
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Last reviewed June 2026 · Methodology & sources